PHOTOBIOMODULATION MODULATES

OXIDATIVE STRESS IN VITRO AND IN VIVO IN CANCER PATIENTS SUFFERING

FROM ORAL MUCOSITIS

Katia Rupel, University of Trieste, Italy

Conflict of Interest DisclosureKatia Rupel DDS, PhD

Has no real or apparent conflicts of interest to report.

OBJECTIVES AND MOTIVATION

Evaluate the effect of PBM on oxidative stress generation

in vivo in oncologic patients suffering from CT/RT-induced OM and in vitro in keratinocytes and neutrophil polymorphonuclear (PMN) granulocytes

Oral mucositis (OM) Photobiomodulation (PBM)

ROS

ROS ROS

ROS

Either limiting ROS generation or increasing their detoxification during CT/RT stands as a rational strategy

to prevent OM onset and/or reduce its severity

Challenges in the local delivery of peptides and proteins for oral mucositismanagement. Campos JC, Cunha JD, Ferreira DC, Reis S, Costa PJ. Eur j Biopharm 2018 Jul; 128:131-146.

MATERIALS AND METHODS

Diode laser (λ 660, 800 and 970 nm)

TOS(Total Oxidative

Status)

CLINICAL STUDY

λ 970 nm, 200 mW/cm2, 6 J/cm2 CW

IN VITRO STUDY

HaCaT keratinocytesPolymorphonucelar granulocytes

i) λ 660 nm, irradiance 50 mW/cm2, fluence 3 J/cm2, CW

ii) λ 800 nm, irradiance 200 mW/cm2, fluence 6 J/cm2, CW

iii) λ 970 nm, irradiance 200 mW/cm2, fluence 6 J/cm2, CW

iv) combined

EVALUATION OF ROS PRODUCTION OVER

TIME WITH AND WITHOUT OXIDATIVE

STIMULUS

TOS

T0#pre

T0#post

T1#pre

T1#post

T2#pre

T2#post

T3#pre

T3#post

CTRL

0

5

10

15

**

*

µmol#H2O

2#equivalents/L

RESULTS1) PBM improves clinical parameters in OM cancer patients and determines a transient reduction in the oxidant status of the saliva

Effectiveness of PBM was confirmed by the progressive decrease of both the VAS and the CTC scores over time, (p = 0.0003 for VAS and p = 0.0034 for CTC).

ROS levels decreased after each PBM session (Mann– Whitney U test p < 0 01 for T1, T2, and T3), increasing again during the following 24 hours, as well as at day 5 (CTRL).

RESULTS2) PBM at different wavelengths differently modulates ROS production in real-time in both PMNs and keratinocytes

PMNs: LPS + DCFH-DA Keratinocytes: H2O2 + roGFP2-Orp1 sensor

λ 660 nm

λ 970 nm

λ 800 nm

ROS

ROS

ROS

RESULTS3) PBM improves keratinocyte resistance to oxidative stress induced by 5-fluorouracil in vitro

We employed the Combined Multi-wavelength protocol in keratinocytes treatedwith 5-fluorouracil (5-FU) mimicking theconditions of OM patients.

PBM reduced cell death following 5-FUtreatment.

PBM significantly lowered the level of ROSproduction in both 5-FU treated anduntreated cells (Mann– Whitney U test p =0.048 and p = 0.015 , respectively).

PBM induced down-regulation of HMOX1 andSOD2, even in cells treated with 5-FU (p =0.03 for both genes).

CELL SURVIVAL ROS PRODUCTION

GENE EXPRESSION

CONCLUSIONS

These findings suggest that a combined multi-wavelength irradiationprotocol may be considered for clinical applications in the preventionand treatment of OM to exploit the different characteristics of singlewavelengths.

“The panel suggests that low-level laser therapy (wavelength around 632.8 nm) be used to prevent oralmucositis in patients undergoing radiotherapy, without concomitant chemotherapy, for head and neckcancer (III).”

Thank You for Your kind attention

Trieste, Italy

!